Hydraulic motors



Jan. 12, 1965 H. R. HALDIMANN HYDRAULIC MOTORS 3 Sheets-Sheet 1 Filed April 8, 1963 r lA/VE/VTO/P Hans A. HALO/MANN Jan. 12, 1965 H. R. HALDIMANN HYDRAULIC MOTORS 3 Sheets-Sheet 2 Filed April 8, 1963 INVENTOR Hans R. HA LD/MA MV ATTORNt-YS H. R. HALDIMANN HYDRAULIC MOTORS s Sheets-S 3 Jan. 12, 1965 Filed Ap 1965 f/afis 1?. HALD/MAN ATTORNEYS United States Patent 3,165,029 HYDRAULIC MOTORS Hans Rudolf Haldimann, Tourneppe-les-Bruxelles, Belgiurn, assignor to AtZEC-Ateliers de Constructions Electriques de Charlerol, 8A., Brussels, Belgium Filed Apr. 8, 1963, Ser. No. 271,367 6 Claims. (Cl. 91-139) The present invention relates to hydraulic motors where in pistons, received in cylinders evenly distributed at the periphery of a stator and provided with piston heads of appropriate shape, successively press on thrust members or abutments made up of cylindrical rollers movable about axles which are mounted on a rotor crown concentric to said stator. More particularly, the invention relates to a motor of the above type, the cylinder axes of which are tangent to an ideal circumference, called the base circumference, concentric to the axis of the motor and the plane of which is perpendicular thereto. Such a motor is described in my United States Patent application Serial No. 234,133, filed October 30, 1962.

Although this motor may, in principle, rotate in both directions, it offers characteristics which are strikingly different for each direction so that, in practice, it is normally used in only one direction of rotation corresponding to its maximum efiiciency.

The object of the present invention resides in the provision of a motor of the above described type wherein the characteristics or features are identical in both directions of rotation. The motor according to the invention is characterized in that its stator is provided with two series of an even number of cylinders the series being mounted side by side in the axial direction of the motor and the axes of the cylinders of each of the series being tangential to an ideal circumference, of equal diameter for both series, concentric to the axis of the motor and the plane of which is perpendicular to the latter axis. It is further characterized in that the axes of the cylinders of the two series cross one another, each of these series corresponding to a direction of rotation of the motor and the heads of the respective pistons acting on the abutments or thrust members of the rotor crown. The hydraulic motor of the invention is further provided with a dis-- tributor, driven by any appropriate means and rotating in a bore of the stator, adapted to successively place each of .the cylinders of a series, corresponding to the desired direction of rotation, in alternative communication with both the high and low feed pressure lines. The distributor is such that, with the piston at the start of its driving stroke, the cylinder is placed in communication with the high pressure feed line and this, until the end of the driving stroke then, from this moment on, successively placing each of the cylinders in communication with the set of cylinders of the other series the pistons of which are adapted to move from the end of the return stroke towards the end of the driving stroke in such a way that, under the force of the moving thrust members, the oil in the cylinders of the first series be transferred into those of the second series, the latter starting with the end of the driving stroke of their pistons, being then placed in communication with the low pressure line where their oil is drawn off.

Further characteristics of the invention will become ap parent from the following description relating to nonlimitative embodiments and having reference to the appended drawings wherein:

FIG. 1 is a development diagram of a motor according to the invention;

FIG. 2 is a double half cross-section view taken along lines AA and BB of FIG. 3;

FIG. 3 is a longitudinal cross-sectional view of the same motor taken along the broken line C-C of FIG. 2, and

FIG. 4 is a schematic elevation view of a speed reduc- 3,165,fi29 Patented Jan. 12, 1965 ing arrangement between the distributor shaft and the rotor.

The motor, diagrammatically illustrated in FIG. 1 has a stator provided with two series of cylinders, the series being arranged side by side in the axial direction of the motor. For each series, the axis of the cylinders are tangential to an ideal circumference which is concentric to the axis of the motor. The diameters of the circumferences corresponding to the two series are equal and the plane of the circumference is perpendicular to the axis of the motor. Furthermore, the axis of the cylinders of the two series cross one another. Pistons are slidably received within said cylinders, those identified by reference numerals 11, 12, 18 corresponding to the first series whereas those identified by numerals 21, 22, 28 correspond to the second series. These pistons are adapted to press on abutments or thrust members constituted by cylindrical rollers freely rotatable about axles which are solid with a rotor crown and are parallel to the axis of the motor. Preferably, there is only one series of thrust members, of sufiicient length so that the heads of the two series of pistons may press thereagainst but there is nothing to prevent, however, to conceive two rotor crowns each having their own thrust members and being solid with one another. In FIG. 1, the thrust members are illustrated by two series of circles; those facing one another are identified by the same reference numerals and it should be accepted that they represent the ends of single thrust mem bers 101, 102 115.

Pistons 11, 12 18 are adapted to cause rotation of the motor in the direction indicated by arrows 1, whereas pistons 21, 22 23 are adapted to cause rotation in the reverse direction. The faces of the piston heads are surfaces which are parallel to the axis of the thrust members and are suitably shaped. What has been said previously in the case of the motor having a single series of tangential pistons described in the above mentioned application is obviously applicable in the instant case.

A distributor, displaceable in the direction of arrow 2 and driven by any appropriate means, is provided in a bore made in the central portion of the stator, axially thereof. A plurality of orifices communicating with the different cylinders of the two series are provided through the said central portion of the stator. This distributor is constituted by a rotary slide valve member 3 which defines, in relation to the bore of stator 4 into which it rotates, two chambers 5 and 6 as well as a conduit 7 adapted to cause intercommunication of a certain number ,of cylinders corresponding to the two series according to a method which will be explained hereinafter.

Chambers 5 and 6 are adapted to be connected respectively to the high pressure line and to the low pressure line or inversely according to the desired direction of rotation of the motor. It will be assumed that chamber 5 is connected to the high pressure line and that chamber 6 is connected to the low pressure line, such an assumption corresponding to the direction of rotation of the motor indicated by arrow 1. In the selected example, the number N of thrust members is equal to 15 whereas the number N of pistons of each of the series is equal to 8. In accordance with what has been said regarding the motor with tangential pistons having only one series of cylinders, these numbers satisfy the relationship N =AN iL It is obvious that the relationship connecting the values and the relative directions of rotation of the speeds of the motor and of the distributor also remain the same. If the situation illustrated in FIG. 1 is taken into consideration, it will be observed that pistons 12, 13, 14 and 15 are under pressure and act on the thrust members with forces tending to have them move in the direction of arrows 1; the cylinders of pistons 22, 2,3, 24 and 25 of the other series are connected to the low pressureand the'cylinders of pistons 17 and 18 of the first series are connected to cylinders of pistons 27 and 28 of the other series through conduit '7 of the distributor. If it is assumed that the slide'valve member 3 of the distributor is moved in the direction of arrow 2, it can be seen that, under the driving force of the pistons 12, 13, 14 and 15 under pressure to which that of piston 16 is added. the rotor first moves through certain angle which corresponds to the position of the end of the driving stroke of piston 12. During that time, piston 11 has been pushed back by thrust member 102 and has thus forced a portion of its oil into the conduit 7. Since piston 21 moves from t e end of the return stroke to the end of the driving stroke While piston 11 does the opposite and that, on the other hand, the faces of the piston heads in contact with the subject thrust members have identical shapes, it can be seen that when, during the continuation of the movement, piston 11 will have reached the end of the return stroke, the oil drawn from its cylinder will be of exactly the same volume as that received in the cylinder of piston 21. The same exchange of oil takes place between the cylinders of pistons 17 and 27 and between those of pistons 18 and 23. It should however be pointed out that, in order that the exchange of oil between the cylinders of the two series takes place practically without friction, it is necessary that to the back movement of a piston correspond an equal forward movement of the corresponding piston and this, at any instant of their stroke. This implies that the implicated face of the head of the piston have a shape such that their stroke be proportional to the angle of rotation of the rotor. However if small irregularities occur, a certain compensation is produced by the fact that the conduit '7 places in simultaneous communication several pairs of corresponding cylinders the pistons of which are at various stroke positions. If such a compensation was insuflicient, useless forces developed by the piston heads on their thrust members would develop during the transfer of oil. This could be remedied, for instance, by connecting conduit 7 to an auxiliary expansion cylinder provided with a piston held up by a 5 calibrated spring, or by foreseeing for the two series of pistons, distinct thrust members secured on two rotor crowns resiliently interconnected. On the other hand, the cylinder of piston 26 of the second series, which was at the end of the driving stroke, was placed in communication with chamber 6 and its oil by means of the distributor. Similarly, the oil of the cylinders of pistons 25, 24:, 23 and 22 which are also pushed back towards the end of their return stroke by the moving thrust members, is progressively drawn off towards the low pressure line.

It follows from the preceding description that the oil, under high pressure is successively admitted in the cylinders of the series which corresponds to the desired direction of rotation then, when the pistons of these cylinders have reached the end of their driving stroke, the oil is transferred, preferably without pressure, in the cylinders of the other series the pistons of which move from the end of their return stroke to the end of their driving stroke. Then, when the latter cylinders are filled, the oil is drawn oif towards the line of low pressure. At any time, the cylinders of the two series are filled with oil and it can easily be seen that by reversing the action of chambers 5 and 6 of the distributor, the motor will be ready to rotate in the other direction with the same characteristics.

It is obvious that all that has been said in relation to the shape of the driving face of the piston heads in the case of tangential piston motor having only one series of cylinders, described in the aforesaid patent application, is also applicable to the motor according to the a present invention. As to the other face, it was seen to be more convenient to give it a shape such as to result in a piston stroke proportional to the angle of rotation of the thrustmember with which it is in contact. It is yet pos- 'sible to give it a further inclination in relation to the axis of the piston such that it may act as a Wedge and by admitting the high pressure in the oil transfer conduit 7, mechanical locking of rotor at rest was obtained by the simultaneous action on the thrust members of the faces in question in the two series of pistons. The motor may thus be maintained at rest against an external driving torque in one direction or the other.

The motor described above is the simplest, its distributor carrying out only one cycle of distribution per turn but, as in the case with the motor having only one series of pistons, it is possible to obtain two or several cycles of distribution per turn of the distributor. It goes without saying that, in all cases, the relationship between the number of thrust members and the number of pistons in a series is the same as in the motor having a single series of pistons and that the ratio and the relative directions of rotation speeds of the motor and of the distributor are also maintained. As an example, one embodiment of a motor according to the invention wherein the distributor carries out two cycles of distribution per turn is illu trated in FIGS. 2 and 3.

The motor illustrated in these figures comprises a stator 36 secured to a frame, not shown, by any convenient means. This motor has a first series of cylinders such as 3i the axes of which are tangential to a base circumference and a second series of cylinders such as 32 the axes of which are tangential to a base circumference of the same diameter as the first base circumference. The axes of the first series cross the axes of the second series. All these cylinders are provided with pistons such as 33 having identical heads of suitable shape and a rotor crown, formed, for instance, of two parts 34 and 35 assembled by bolts as and nuts 37. Bolts 35 serve as axles of rotation for thrust members constituted by cylindrical rollers 33 on which the piston heads of the two series of cylinders abut.

The cylinders open into a bore 3? of the stator by orifices such as 4% for the first series and 41 for the second. In this here, rotates a distributor 2 driven, through the medium of a shaft 43, by any suitable means and in the direction corresponding to the desired direction of rotation of the motor. For instance, shaft 43 of the distributor may be driven independently of the hydraulic motor by an auxiliary motor 6 connected to a power source 61 and controlled by a speed controller 62. Distributor shaft 43 may also be driven by a gear train 63 meshing with an internal gear 64 secured to the rotor of the hydraulic motor, as more particularly illustrated in FIG. 4, the said gear train 53 providing a predetermined multiplication ratio and being disposed so that the distributor rotates in the same direction as the rotor, as said previously. This distributor defines, in relation to bore 3?, two chambers 44- and 4-5 which communicate respectively, through annular grooves 47 and with channels 49 and 48 opening outwar ly of the stator and adapted to be connected respectively to the high pressure line and to the low pressure line or inversely according to the direction of rotation of the motor. The distributor also defines, in relation to bore 3%, oil transfer channels and 51 interconnecting corresponding cylinders of the two series according to the process explained above.

The transfer channels 5d and 51 communicate, through an annular groove 52, with a conduit 53 opening outwardly of the stator and adapted to be joined to the high pressure line for the purpose of locking the motor at rest according to the process explained above.

The rotor crown transmits its torque for use through any convenient means, not shown; for instance, part 34 may be provided, at its periphery, with gear teeth or it may form a coupling flange.

The motor described above operates according to the manner explained in relation to FIGURE 3 but its distributor carries out two cycles of distribution per turn. it comprises, per series, nine pistons and 20 thrust memhaving only a single series of cylinders obviously applies to the motor according to the invention.

The invention is not to be limited to the specific'embodiments described; it is possible, for instance, to imagine a motor having the form of a circular sector. in which case it would moveonly a limited angle of rotation, in one direction or the other; rectilinear rack.

Other embodiments may be imagined Without departing from the spirit of the present invention.

I claim:

1. In a hydraulic motor having a central stator, an

outer peripheral rotor concentric thereto and a plurality of thrust members on said rotor, the combination comprising:

(a) two series of an equal number of cylinders, atthe periphery of said stator, the series being arranged side by side axially of the stator;

(la) the axes of the cylinders ofeach series being tangential to a base circumference concentric to the axis of the stator; 1

it may also have the form of a (c) the base circumferences being equal in diameter and perpendicular to the axis of the stator;

(d) the axes of the cylinders of one series crossing the axes of the cylinders of the other series; each series corresponding to a direction of rotation of the stator;

(e) a distributor mounted for rotation in a central axial bore of said stator;

(f) a piston, slidable in each cylinder, having a head adapted to rest on said thrust members; (g) means, in said distributor, successively communicating each of the cylinders corresponding to the desired direction of said motor and the piston of which is at the start of its working stroke with a source of high pressure until the end of said working stroke and then successively communicating each of said cylinders with all of the cylinders of the other series, the pistons of which are displaceable from the end of the return stroke towards the end of the working stroke in such a way that under the action of the moving thrust members, the oil in the cylinders of the first series moves to those of the second series, the latter being thereafter, and from the end of their driving stroke, placed in communication with a low pressure line where the oil is drawn oif.

2. Motor according to claim 1 wherein the face of the head of the pistons which, in the series producing the workingstroke, is pushed by the thrust members, is

shaped in such a Way that the return stroke of the concerned pistons is proportional to the angle of rotation of the rotor. t

3. A motor as claimed in claim 2, characterized inthat the number of abutments plus or minus the number of cycles of distribution per turn of the distributor is equal to the number of pistons of a series or to a multiple thereof.

4. A motor according to claim 1 wherein the distribu tor is driven by the rotor, in a predetermined direction, through a speed multiplier the ratio of which is equal to the number of thrust members divided by the number of cycles of distribution per turn of the distributor.

5. A motor according to claim 1, wherein the distributor is driven by means outside the rotor in such a way that the latter rotates in synchronism with the distributor in a step on ratio equal to the number of thrust members divided by the number of cycles of distribution per turn of the distributor. i

A motor according to claim 1, wherein the channelsfor the transfer of the oil of the distributor, placing into comniunication a certain number of cylinders of the two series, are connected through an annular groove to a channel provided in the stator and adapted to be placed under high pressure in such a way that the piston heads, in each of the two series, act on the thrust members in the manner of wedges so as tolock the rotor at rest, the acting faces of the heads of the piston being suitably inclined in relation to the axis of the pistons.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A HYDRAULIC MOTOR HAVING A CENTRAL STATOR, AN OUTER PERIPHERAL ROTOR CONCENTRIC THERETO AND A PLURALITY OF THRUST MEMBERS ON SAID ROTOR, THE COMBINATION COMPRISING: (A) TWO SERIES OF AN EQUAL NUMBER OF CYLINDERS, AT THE PERIPHERY OF SAID STATOR, THE SERIES BEING ARRANGED SIDE BY SIDE AXIALLY OF THE STATOR; (B) THE AXES OF THE CYLINDERS OF EACH SERIES BEING TANGENTIAL TO A BASE CIRCUMFERENCE CONCENTRIC TO THE AXIS OF THE STATOR; (C) THE BASE CIRCUMFERENCES BEING EQUAL IN DIAMETER AND PERPENDICULAR TO THE AXIS OF THE STATOR; (D) THE AXES OF THE CYLINDERS OF ONE SERIES CROSSING THE AXES OF THE CYLINDERS OF THE OTHER SERIES; EACH SERIES CORRESPONDING TO A DIRECTION OF ROTATION OF THE STATOR; (E) A DISTRIBUTOR MOUNTED FOR ROTATION IN A CENTRAL AXIAL BORE OF SAID STATOR; (F) A PISTON, SLIDABLE IN EACH CYLINDER, HAVING A HEAD ADAPTED TO REST ON SAID THRUST MEMBERS; (G) MEANS, IN SAID DISTRIBUTOR, SUCCESSIVELY COMMUNICATING EACH OF THE CYLINDERS CORRESPONDING TO THE DESIRED DIRECTION OF SAID MOTOR AND THE PISTON OF WHICH IS AT THE START OF ITS WORKING STROKE WITH A SOURCE OF HIGH PRESSURE UNTIL THE END OF SAID WORKING STROKE AND THEN SUCCESSIVELY COMMUNICATING EACH OF SAID CYLINDERS WITH ALL OF THE CYLINDERS OF THE OTHER SERIES, THE PISTONS OF WHICH ARE DISPLACEABLE FROM THE END OF THE RETURN STROKE TOWARDS THE END OF THE WORKING STROKE IN SUCH A WAY THAT UNDER THE ACTION OF THE MOVING THRUST MEMBERS, THE OIL IN THE CYLINDERS OF THE FIRST SERIES MOVES TO THOSE OF THE SECOND SERIES, THE LATTER BEING THEREAFTER, AND FROM THE END OF THEIR DRIVING STROKE, PLACED IN COMMUNICATION WITH A LOW PRESSURE LINE WHERE THE OIL IS DRAWN OFF. 